/*
 * Copyright 2015-2102 RonCoo(http://www.roncoo.com) Group.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.roncoo.pay.app.settlement.utils;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 线程池工具类
 * 龙果学院：www.roncoo.com
 *
 * @author zenghao
 */
public class SettThreadPoolExecutor {
    private static final Log LOG = LogFactory.getLog(SettThreadPoolExecutor.class);
    /**
     * 针对核心Thread的Max比率 ，以10为基数，8表示0.8
     */
    private int notifyRadio = 4;

    /**
     * 最少线程数.<br/>
     * 当池子大小小于corePoolSize就新建线程，并处理请求.
     */
    private int corePoolSize;

    /**
     * 线程池缓冲队列大小.<br/>
     * 当池子大小等于corePoolSize，把请求放入workQueue中，池子里的空闲线程就去从workQueue中取任务并处理.
     */
    private int workQueueSize;

    /**
     * 最大线程数.<br/>
     * 当workQueue放不下新入的任务时，新建线程入池，并处理请求，<br/>
     * 如果池子大小撑到了maximumPoolSize就用RejectedExecutionHandler来做拒绝处理.
     */
    private int maxPoolSize;

    /**
     * 允许线程闲置时间,单位：秒.<br/>
     * 当池子的线程数大于corePoolSize的时候，多余的线程会等待keepAliveTime长的时间，如果无请求可处理就自行销毁.
     */
    private long keepAliveTime;

    private ThreadPoolExecutor executor = null;

    public void init() {
        if (workQueueSize < 1) {
            workQueueSize = 1000;
        }
        if (this.keepAliveTime < 1) {
            this.keepAliveTime = 1000;
        }
        int coreSize = 0;
        if (this.corePoolSize < 1) {
            coreSize = Runtime.getRuntime().availableProcessors();
            maxPoolSize = Math.round(((float) (coreSize * notifyRadio)) / 10);
            corePoolSize = coreSize / 4;
            if (corePoolSize < 1) {
                corePoolSize = 1;
            }
        }

        // NOTICE: corePoolSize不能大于maxPoolSize，否则会出错
        if (maxPoolSize < corePoolSize) {
            maxPoolSize = corePoolSize;
        }

        /**
         * ThreadPoolExecutor就是依靠BlockingQueue的阻塞机制来维持线程池，当池子里的线程无事可干的时候就通过workQueue.take()阻塞住
         */
        BlockingQueue<Runnable> notifyWorkQueue = new ArrayBlockingQueue<Runnable>(workQueueSize);

        executor = new ThreadPoolExecutor(corePoolSize, maxPoolSize, keepAliveTime, TimeUnit.SECONDS, notifyWorkQueue, new ThreadPoolExecutor.CallerRunsPolicy());

        LOG.info("NotifyExecutor Info : CPU = " + coreSize +
                " | corePoolSize = " + corePoolSize + " | maxPoolSize = " +
                maxPoolSize + " | workQueueSize = " + workQueueSize);
    }

    public void destroy() {
        executor.shutdownNow();
    }

    public void execute(Runnable command) {
        executor.execute(command);
    }

    public void showExecutorInfo() {
        LOG.info("NotifyExecutor Info : corePoolSize = " + corePoolSize +
                " | maxPoolSize = " + maxPoolSize + " | workQueueSize = " +
                workQueueSize + " | taskCount = " + executor.getTaskCount() +
                " | activeCount = " + executor.getActiveCount() +
                " | completedTaskCount = " + executor.getCompletedTaskCount());
    }


    public void setNotifyRadio(int notifyRadio) {
        this.notifyRadio = notifyRadio;
    }

    public void setWorkQueueSize(int workQueueSize) {
        this.workQueueSize = workQueueSize;
    }

    public void setKeepAliveTime(long keepAliveTime) {
        this.keepAliveTime = keepAliveTime;
    }

    public void setCorePoolSize(int corePoolSize) {
        this.corePoolSize = corePoolSize;
    }

    public void setMaxPoolSize(int maxPoolSize) {
        this.maxPoolSize = maxPoolSize;
    }
}
